The present invention is related to the field of power supplies or ballasts for relatively high-power LED lamps used for area lighting.
There is increasing use of high-power light-emitting diodes (LEDs) to construct light fixtures or lamps used for area lighting, replacing the more traditional incandescent or fluorescent types of lamps. LED-based lighting can provide several benefits including improved efficiency and greater control over both the physical packaging and the light output characteristics of light fixtures. As the light from a given LED is typically limited, LED lamps typically employ a number of LEDs operating together to achieve a desired light output. In one configuration, LEDs are connected together in series and a relatively high lamp voltage (generally proportional to the number of series-connected LEDs) is used. The light output of the lamp may be controlled by a lamp power supply that regulates lamp current to a desired level which corresponds to the normal operating light output of the lamp.